1. Field of the Invention
The present invention relates to food packages in general, and in particular, to food receptacles for use in the microwave cooking of foods which incorporate therein provisions for the browning of the exterior of the food in the receptacle.
2. Description of the Prior Art
It is of general concern in the art of microwave cooking that the exterior of the food being cooked is browned so as to more closely resemble food cooked by conventional methods. If a special provision is not made for browning the exterior of the food, the exterior of the food cooked in a microwave oven will remain undercooked because of the surface cooling effect of the food as it is heated by microwave radiation. Therefore it has been a general object within the art of microwave cooking of foods to perfect an economical and efficient method for browning the exterior of the foods being cooked in a microwave oven.
The prior art is generally cognizant, therefore, of various attempts to incorporate layers into receptacles used for the microwave cooking of foods, which layers are designed to be particularly susceptible to being heated by microwave radiation. Such layers are conventionally made of semiconductive materials such as tin oxide. Examples of U.S. patents showing the use of such layers can be seen in U.S. Pat. Nos. 3,853,612, and 3,965,323. Other examples of methods used to obtain browning heat from microwave radiation are shown in U.S. Pat. Nos. 2,582,174, 3,701,872, 3,773,669, and 4,003,840.
In addition at least one example is known of a method of heating foods in a microwave oven which incorporates therein the use of ferro-magnetic metals. Such example is shown in U.S. Pat. No. 2,830,162. In addition at least one U.S. patent teaches the incorporation of an electrically conductive film in a ceramic dish or other heavy vessel for use in the browning of foods cooked in a microwave oven. However, the examples shown in that patent, which is U.S. Pat. No. 3,783,220, are directed to a film of tin oxide, with alternative substances disclosed being cellulose fiber and silicon carbide. No example of such a container for use in the browning of foods in a microwave oven is known in the prior art which incorporates therein the use of an elemental metal, nor the use of an extremely thin conductive film on a low cost, disposable substrate.